[Delphi]DBGrid Column-Width 欄位寬度自動最佳化
DBGrid會以資料長度自行調整寬度，所以Column的寬度，常常落落長，
所以寫一個方法，來自行最佳化。
※原理說明：利用Canvas的方法TextWidth取得文字寬度，進行調整過程中，先以Field的文字進行寬度最佳化後，
再以Column->Title->Caption(以避免Field的內容為空值)
1: procedure FitDBGridWidth(DBGrid:TInfoDBGrid;MaxRecNo:Integer);
2: var FieldIdx, I : Integer;
3: MaxFieldLen: Array Of Integer;
4: FieldName:Array Of String;
5: SavePlace:TBookmark;
6: Canvas: TCanvas;
7: AfterScroll:TDataSetNotifyEvent;
8: begin
9: Canvas := DBGrid.Canvas;
10: if (DBGrid.DataSource.DataSet.State
11: in [dsInactive, dsInsert, dsEdit])
12: or(DBGrid.DataSource.DataSet.IsEmpty = True) then Exit;
13: try
14: AfterScroll:=DBGrid.DataSource.DataSet.AfterScroll;
15: DBGrid.DataSource.DataSet.AfterScroll:=nil;
16: with DBGrid.DataSource.DataSet do
17: begin
18: SavePlace := GetBookmark; //原始位置
19: SetLength(MaxFieldLen,DBGrid.DataSource.DataSet.FieldCount);
20: SetLength(FieldName,DBGrid.DataSource.DataSet.FieldCount);
21: DBGrid.DataSource.DataSet.DisableControls;
22: DBGrid.DataSource.DataSet.First;
23: while Not DBGrid.DataSource.DataSet.Eof do begin
24: For I := 0 to DBGrid.DataSource.DataSet.Fields.Count - 1 DO
25: BEGIN
26: FieldName[I]:=DBGrid.DataSource.DataSet.Fields[I].FieldName;
27: IF (Canvas.TextWidth(DBGrid.DataSource.DataSet.Fields.Fields[I].DisplayText) + 4) > MaxFieldLen[I] Then
28: MaxFieldLen[I] := Canvas.TextWidth(
29: DBGrid.DataSource.DataSet.Fields.Fields[I].DisplayText) + 4
30: END;
31: DBGrid.DataSource.DataSet.Next;
32: if DBGrid.DataSource.DataSet.RecNo>MaxRecNo then Break;
33: end;
34: DBGrid.DataSource.DataSet.First;
35: DBGrid.DataSource.DataSet.EnableControls;
36:
37: for I := Low(FieldName) to High(FieldName) do
38: begin
39: FieldIdx:= ColIndexOf(DBGrid, FieldName[I]);
40: IF FieldIdx = -1 then Continue;
41: IF (DBGrid.Columns.Items[FieldIdx].Visible) then begin
42: if MaxFieldLen[I]>(Canvas.TextWidth(DBGrid.Columns[FieldIdx].Title.Caption)+4) then begin
43: if MaxFieldLen[I]>300 then
44: DBGrid.Columns.Items[FieldIdx].Width := 300
45: else
46: DBGrid.Columns.Items[FieldIdx].Width := MaxFieldLen[I];
47: end
48: Else
49: DBGrid.Columns.Items[FieldIdx].Width:= (Canvas.TextWidth(DBGrid.Columns[FieldIdx].Title.Caption)+4);
50: end
51: ELSE DBGrid.Columns.Items[FieldIdx].Width := -1;
52: end;
53: GotoBookmark(SavePlace); //回到 原始位置
54: FreeBookmark(SavePlace);
55: end;
56: finally
57: DBGrid.DataSource.DataSet.AfterScroll:=AfterScroll;
58: end;
59: end;
料理方法：
1: //將DBGrid進行欄位寬度最佳化，以前50筆進行取樣2: FitDBGridWidth(grdDetail,50);